Field
The disclosed concept relates generally to electrical power systems and, more particularly, to electrical distribution assemblies. The disclosed concept relates to dielectric materials of high thermal conductivity that can be molded or assembled into electrical distribution assemblies to act as heat transfer windows that dissipate heat generated in and/or around electrical distribution assemblies. The disclosed concept further relates to methods for removing heat from an electrical switching device.
Background Information
Electrical distribution assemblies generally include electrical switching devices. When current runs through an electrical switching device, heat is generated by components of the electrical switching device. As a result of this heat, the temperature within and around the electrical switching device, and more generally the electrical distribution assembly, tends to increase. This heat, if it becomes excessive, can cause various events to occur, including but not limited to damage to components, other devices, premature activation of trip mechanisms, and other malfunctions. In addition, electrical distribution assemblies and electrical switching components therein may include other circuitry, such as control circuitry, which further generate heat within and around electrical distribution assemblies. Likewise, as electrical distribution assemblies and electrical switching devices therein are developed with greater complexity, the heat generated throughout the electrical distribution assembly and electrical components may increase. As a result of this potential increase in heat, it may become somewhat difficult for the electrical distribution assemblies and electrical switching devices to operate within the given temperature ranges established by various safety organizations as an industry standard. These codes include, but are not limited to, the UL-67 safety codes, which include requirements that temperatures within electrical distribution assemblies not exceed 50 degrees centigrade over ambient.
Accordingly, it is desirable to couple thermally conductive materials to various components of electrical distribution assemblies and the electrical switching devices therein to transfer heat away from those components. As such, electrical distribution assemblies and electrical switching devices generally include at least some thermally conductive materials coupled to various heat generating components. However, due to cost constraints, potential structural weakness, and various other inefficiencies related to these thermally conductive materials, a better thermally conductive material for performing the vital task of heat transfer is needed. For example, thermal interface materials (“TIM”), poly-phenylene oxide (“PPO”), and epoxy resin assemblies are known to be thermally conductive and electrically insulating, and thus are used to transfer heat from vulnerable components in an electrical distribution assembly. However, PPO and epoxy resin insulation products often lack the desirable strength to maintain structural integrity under extreme conditions for desirable periods of time, and as such have a tendency to break apart. Additionally, in some instances relating to electrical distribution assemblies involving electrical conductors, TIMs may provide insufficient thermal conductivity unless they are of a sufficiently thermally conductive variety that tends to be prohibitively expensive. For example, a thermal coupling of certain TIMs to various materials generally found within an electrical switching device may result in what is called an “air gap,” whereby a small space is present at the point of coupling between the TIM and the material. This results in a reduction of the thermal conductivity of the TIM, and thus reduces the amount of heat that may be transferred away from the vulnerable components. Additionally, TIMs generally are limited to a thermal conductivity of roughly 1 W/(m·K) before becoming prohibitively expensive.
There is thus room for improvement in electrical power systems, and in electrical distribution assemblies and the components therein.